The diagnosis of a child with autism has short- and long-term impacts on family functioning. With early diagnosis, the diagnostic process is likely to co-occur with family planning decisions, yet little is known about how parents navigate this process. This study explores family planning decision making process among mothers of young children with autism spectrum disorder in the United States, by understanding the transformation in family vision before and after the diagnosis. A total of 22 mothers of first-born children, diagnosed with autism between 2 and 4 years of age, were interviewed about family vision prior to and after their child's diagnosis. Grounded Theory method was used for data analysis. Findings indicated that coherence of early family vision, maternal cognitive flexibility, and maternal responses to diagnosis were highly influential in future family planning decisions. The decision to have additional children reflected a high level of adaptability built upon a solid internalized family model and a flexible approach to life. Decision to stop child rearing reflected a relatively less coherent family model and more rigid cognitive style followed by ongoing hardship managing life after the diagnosis. This report may be useful for health-care providers in enhancing therapeutic alliance and guiding family planning counseling.